In recent years, social networks have found increasing popularity. Social networks are known to enjoy the benefits of a network effect, wherein the increase in the size of the social network also increases the perceived benefits of using it. Much of this benefit is embedded in the information flows in the social network. The information flows arise as a result of the communication between the different entities in the social network. As such, social networks serve as a useful tool for dissemination of information between individuals on large networks. A challenge, however, exists in determining relevant and/or important nodes in such networks.
An information flow can be impacted, for example, by the network topology and the intensity of information flow interactions between different nodes. Also, information flow authorities are defined as a small group of members at which the dissemination of information leads to the most rapid spread throughout a social network. The concept of information authorities is peripherally related to that of the concept of hubs and authorities in web networks. The concept of hubs and authorities is used to find central points of influence in web networks. However, the concept of information flow authorities is different from that of the hub-authority framework, in that it is more dependent upon the structure of the flows along the underlying network. This is dependent both upon the structural characteristics of the network and the flow intensity along different edges.
The flow authorities in a social network are likely to be central and well connected entities in the network. However, the local structural measures alone do not provide a global view of the {\em centrality of flows} in a social network. Additionally, a related challenge is that of virus propagation in computer networks and epidemic spreading.